The present invention relates to a technique for transferring tape information between a plurality of computer systems. There are magnetic tapes as conventionally used recording media which provide access at a speed lower than that of magnetic disk drives. As exemplified in Japanese Unexamined Patent Application Publication No. Hei 11-272426, in recent years, there have been developed virtual tape units which permit access faster than actual magnetic tapes by virtually emulating the tape units on magnetic disk drives capable of access at a higher speed.